The present invention relates to an LED backlight device and an LCD device using the LED backlight device.
A general LED (Light Emitting Diode) backlight device includes individually molded LED elements arranged at suitable intervals. An LCD (Liquid Crystal Display) panel is provided facing the LED backlight device so as to constitute an LCD device, and a light diffusion plate is provided between the LED backlight device and the LCD panel for uniformly illuminating the LCD panel.
To be more specific, the conventional LCD device using the LED backlight device includes a prism sheet provided on the backside of the LCD panel, a first diffusion plate disposed on the backside of the prism sheet, a plurality of LED elements (i.e., individually molded LED elements that emit white lights) mounted on a substrate disposed on the backside of the first diffusion plate, and a second diffusion plate disposed on the backside of the substrate. The second diffusion plate is attached to a window for introducing external light. The LCD panel is uniformly illuminated with white light emitted by the white LED elements and the external light (see, for example, Patent Document 1).
Another conventional LCD device using the LED backlight device includes a light diffusion plate (having convexes and concaves) disposed on the backside of the LCD panel, a plurality of LED elements (i.e., individually molded LED elements that emit lights of primary colors) mounted on a substrate disposed on the backside of the light diffusion plate, and a reflection plate provided covering a surface of the substrate around the LED elements for enhancing intensity of light illuminating the LCD panel. Further, heat sinks or heat pipes are provided between the LED elements and the substrate for dissipating the heat generated by the LEDs (see, for example, Patent Document 2).
Patent Document 1: Japanese Laid-open Patent Publication No. 2002-311412
Patent Document 2: Japanese Laid-open Patent Publication No. 2004-319458